Cocaine abuse is common among schizophrenics. In fact, the Epidemiological Catchment Area study found that 16.7% of cocaine addicts had a comorbid diagnosis of schizophrenia (odds ration of 13), and 47% of schizophrenics have a lifetime substance use disorder. These individuals respond poorly to traditional drug abuse and psychiatric treatments. There exists a great clinical and research need to develop innovative and well defined psychopharmacological treatments for this population which address both the psychiatric and substance abuse problems. This grant application proposes to evaluate pharmacotherapies for schizophrenic cocaine abusers and proposes to begin with a 12 week double blind trial comparing adjunctive mazindol versus placebo. All patients will be maintained on neuroleptic medication for schizophrenia. Also, patients will be randomized to either a day hospital (25 hours / week) or an intensive outpatient program (12 hours / week). Both of these dual diagnosis programs emphasize group therapy, but include individual case management and family participation. The core psychotherapy approach for the program is Dual Diagnosis Relapse Prevention (DDRP) which consists of modified substance abuse relapse prevention and psychiatric social skills training (psychiatric symptom and medication management). After the 12 week clinical trial, patients will be re-evaluated at three and six month follow-up sessions. The specific aims of this grant proposal are to: 1. Determine the efficacy of adjunctive mazindol in improving substance abuse treatment outcomes in schizophrenic cocaine abusers. 2. Compare the relative efficacy of the two levels of psychosocial treatment (including cost-effectiveness). 3. Stratify by gender and assess differences in treatment outcome. 4. Assess predictors of treatment efficacy including severity of cocaine usage, negative symptoms of schizophrenia and depression.